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I have a simple table in PostgreSQL 8.2.5:

CREATE TABLE power_transitions (
-- Transition ID (PK)
tid integer NOT NULL,
-- State ID (0 = Unknown, 1 = Online (AC power), 2 = Offline (Battery)
sid smallint NOT NULL,
-- Timestamp of transition
statetime timestamp without time zone DEFAULT now() NOT NULL,
-- Is this a real outage?
is_outage boolean DEFAULT true NOT NULL
);

It contains a log of power outages (transitions). I'd like to create
query that returns a transition offline time and associated return to
online time. Is there a better way of handling this? I am open to
schema change suggestions. Thanks very much!

-- Gary Chambers

// Nothing fancy and nothing Microsoft!